Capacitive memory storage device employing magnetizable material as a dielectric



Mam}! 1969 E. o. OLSEN 3,434,120

CAPACITIVE MEMORY STORAGE DEVICE EMPLOYING MAGNETIZABLE MATERIAL AS ADIELECTRIC Filed Oct. 14, 1965' INVENTQR. EVERETT O. OLSEN BYDWMECH'WLATTORNEY 1 United States Patent 2 Claims ABSTRACT OF THE DISCLOSURE Acapactive memory storage device employs a magnetizable material as adielectric sandwiched between two electrically conducting members; thecombination has a capacitance dependent upon the magnetization of thedielectric; a quantity is stored in the device by magnetizing thedielectric to a degree related to the quantity, which stored amount maybe read at any time in terms of the device capacitance until such timeas the magnetic state is again altered.

This invention relates to storage devices and more particularly to acapacitive memory employing a dielectric that may be varied bymagnetization means.

An object of this invention is to provide a memory device controlled bymagnetizing means having a variable capacitive readout.

Another object of this invention is to provide a memory device whosecapacity is related to the condition of its magnetization.

Another object of this invention is to provide a memory device having anon-destructive readout.

Another object of this invention is to provide a means for storing adigit according to magnetic switching of a core and employing anon-destructive capacitive readout means therewith.

Another object of this invention is to provide a memory device employinga magnetically-controlled core having a dielectric property influencingthe capacity of readout means associated therewith.

Another object of this invention is to provide a magnetically-controlledmemory device having a non-destructive resistive read-out.

Other objects and advantages of this invention will he in part apparentfrom the specifications and in part from the figure, which is:

A view of the memory device of the invention showing a dielectric corebetween capacitive elements and including magnetizing means and read-outterminals therewith.

Referring now to the figure, core is composed of a magnetizable materialwhose dielectric constant varies with the degree of magnetization.Ferrites, for example, have medium to high dielectric constants withsome in the order of 500,000. It is also convenient to employ in thisembodiment a core having a high resistance thereby enhancing the storagecharacteristic of the invention. Sandwiching core 10 are two conductingplates 11 and 12 composed of any material having good electricalconductivity. Winding 13 loops about the core sandwich comprised ofmagnetizable material 10 and conducting plates 11 and .12 therebyproviding a means of magnetizing core 10. Winding 13 has input terminals14 and 15 to which may be applied a pulse of positive or negativepolarity, or to which may be applied an analog signal having a variabledegree of magnitude.

The state of magnetization of core 10 determines its dielectric constantat any instant, and conducting plates 11 and 12 comprise the plates of acapacitive element whose capacity is influenced and determined by thedielectric constant of core 10 therebetween. Terminal 18 connected toplate 1.1 and terminal 19 connected to plate 12 form the read-outterminals of the capacitor comprised of plates 11-12. Terminals 18 and19 may be connected to any capacity-determiningmeans such as the tunedcircuit of an oscillator, the variable leg of a capacitor bridge, or toa momentary switching means in which charging current will be determinedby the combination of capacity and degree of previous charge.

It may be seen that the applications of such a device are many, as it issimple in construction and offers the combination of non-destructiveread-out from its capacitive element and further ofiers a number ofpossibilities of applications utilizing advantages related to theintegrating characteristics derived from its chargeable feature.

As an alternative embodiment of the invention of the figure, terminals18 and 19 are employed to read the resistance of core 10. The resistanceof core 10 will change with its degree of magnetization, and terminals18 and 19 will therefore offer a means of sampling the magnetizationstatus and degree of core 10. In this embodiment a relatively lowresistance core may be convenient for more easily detecting changes inits resistance by an output sensing device resulting from magnetizationchange in the core. High resistance core materials may also be usedhaving sufiicient resistive change therein related to the extent of coremagnetization.

Core 10 may be rectangular or round, or any shape Which may beconveniently affected by magnetizing means and adaptable for use inconjunction with any number of capacitance elements 11-12 serving ascapacitive areas or plates. It is to be understood that the platesherein may be of any size and may consist only in the electricalterminal 20 itself employed to connect the core to an output. Multiplecapacitance elements may be used, or duplicate pairs associated witheach core, to facilitate multiple substantially non-interacting outputsfor purposes such as setting up a matrix logic for reading out on an x-yor x-yz matrix designation.

It has been found that configurations of members 11 and 12 arepracticable which are not adjacent winding 13 so that winding 13 doesnot influence the electrical constant, capacitance or resistance, to bedetected between the members 11 and 12. That is to say, winding 13 maybe only wound about core 10 itself.

Applications requiring either a variable capacitive element or avariable resistive element which are varied by control means and whichare to retain their analog value until recontrolled may be appropriate,such as in selftuning means for an R-F stage, or in means for the tuningof a process controller. It is apparent that the invention is adaptableto the entire range of digital applications in which each unit mayrepresent a discrete number of states, usually two.

While there has been shown what is considered to be a preferredembodiment of the invention, it Will be manifest that many changes andmodifications may be made therein without departing from the essentialspirit of the invention.

What is claimed is:

1. A memory device having a variable capacitive condition dependent uponchanges in state of magnetization comprising:

3 a core including magnetizable material capable of retaining amagnetized condition, at least two electrically conducting membersdisposed adjacent said core to include said core in the dielectric pathbetween said members, means responsive to an analog signal having avariable degree of magnitude associated with said core for changing thestate of magnetization of said core in accordance with said magnitude,and means interconnected with said conducting members for sampling thevalue of the electrical capacity between said members resulting from thestate of magnetiz-ation of said core and which value is related tochanges in the state of magnetization of said core and which valuerepresents a quantity stored by said means for changing themagnetization of said core. 2. The memory device of claim 1 Wherein saidmeans for sampling is adapted to distinguish said electrical capacityover a continuously variable range of values related to the state ofmagnetization of said core.

December 1959, p. 33.

References Cited UNITED STATES PATENTS OTHER REFERENCES W. K. French:Chopper, IBM TDB vol. 2, N0. 4,

15 BERNARD KONICK, Primary Examiner.

JOSEPH F. BREIMAYER, AS- siS/(Int Examiner.

US. Cl. X.R.

